Field of the Invention
The invention relates in general to a bitstream decoding method and an associated bitstream decoding circuit, and more particularly to a temporal scalable video bitstream decoding method and an associated bitstream decoding circuit capable of alleviating a decoding load and smoothly playing a video.
Description of the Related Art
A video is capable of presenting vivid visual information, and the video display function is also a development focus of modern electronic products. A video is a series of sequentially arranged frames. To facilitate the storage and transmission of the video, the frames in the video are encoded into a bitstream. To realize the video display function, these frames need to be first decoded from the bitstream before they can be played.
Video decoding may be performed by a hardware or software decoder. The decoding capability of a decoder is limited by the specifications of the decoder. If the frame rate of the video exceeds the specification of the decoder, the video cannot be smoothly displayed. For example, a decoder supporting a specification of 60 frames per second (fps) means that this decoder can decode and provide 60 frames maximum per second, and a video having a frame rate of 120 fps is considered over-spec for the decoder having a frame rate of 60 fps. If a decoder having a frame rate of 60 fps is applied for a video having a frame rate of 120 fps, the video cannot be smoothly displayed. Further, even if a video that does not exceed the specification of a decoder can be displayed, in the event that other software (e.g., a foreground application program) or firmware requests the decoder to release or suspend a part of the system resources during a display process of the video, the decoding capability of the decoder is also undesirably affected, and the number of decoded frames within unit time is then decreased.